Tobacco process, and product



United States Patent Q 3,039,475 TOBACCO PROCESS, AND PRODUCT SergeNeukomm, Prilly, andJacques Bonnet, Lausanne, Switzerland, assignors toSasmoco S.'A.,'Lenzerheide, Grisous, Switzerland No Drawing. Filed Apr.13, 1959, Ser..No. 805,664 Claims priority, application Switzerland Apr.11, 1958 .9 Claims. (Cl. 131--140) It is well known to those skilled inthe art that tobacco smoke contains certain carcinogenic. substances andthat these substances are not present in the tobacco itself but areformed during the combustion of the tobacco and are therefore present inthe tobacco smoke.

Our invention relates to a new and improved process for treating orimpregnating tobacco.

It is an object of the invention to provide a method for treatingtobacco for the purpose of modifying its combustion process to therebydiminish the amount of the carcinogenic substances formed during thecombustion, particularly of polycyclic hydrocarbons such as3,4-benzo-pyrene.

A further object of the invention is the provision of a method capableof modifying the surface of the vegetative fiber of tobacco and thepermeability of the vegetative cells therein.

The result of the treatment according to our invention is that the smokeof the treated tobacco contains less carcinogenic hydrocarbons and alsoless irritating and carcinogenic polymeric substances which are usuallyformed by combustion of untreated tobacco. Further objects of theinvention will appear in the course of the following detaileddescription of our invention.

The new process for treating tobacco broadly stated comprisesimpregnating tobacco with a substance containing a metallic componentand at least one permeabilitymodifying agent taken from the class ofhalogenated hydrocarbons generally known as organic solvents, i.e.volatile liquids which are non-inflammable due to their halogenation.The treatment of tobacco is carried out in two steps which are:

First, an operation of preparing the fiber of tobacco by a careful andmild action of the permeability-modifying agent which preferably is anorganic solvent, which has the eifect of modifying the surface of thevegetative fiber and consequently the permeability of the vegetativecells themselves;

Second, an operation of actual impregnation by the action of animpregnating mixture consisting of (l) a volatile, non-inflammableliquid of the class known as organic solvents which preferably is thesame as the permeability modifying agent used in the first step, and (2)less than of a metal substance in the form of an organo-metalliccompound in solution, or a metal, a metal oxide or a metal salt insuspension in said liquid acting as solvent or dispersant, respectively;these solutions or suspensions will be referred to in the followingspecification as impregnation mixtures.

Concerning such impregnation mixtures it will be noted that if thesemixtures are formed by a solution the organometal compound can penetrateinside the vegetative cells; but, if the impregnation mixture is asuspension, the small particles of metal, metal oxide or metal salt arefixed on the surface of the fibers which have been prepared by theaction of the permeability-modifying agent during the above mentionedfirst step.

The metal component can be an organo-metallic compound, preferably of abivalent or trivalent metal such as aluminum, magnesium, cadmium,bismuth or iron, e.g. in the form of their alcoholates which arepreferred because of their good solubility, or of their organo-metallicacids,

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the metal being preferably attached to the carbon atom in them-positionof the carboxylic radical, e.g. aluminum diethyl malonate. Theseorgano-metal compounds are used in solution. The metal component can,however, just as well be an elemental metal or a metal oxide or a metalsalt which is transformed into an elemental metal or a metal oxideduring the combustion of tobacco,,.i.e. at a temperature of about 500 C.and above. Such compounds comprise e.g. aluminum, magnesium, manganese,cadmium, bismuth, iron, platinum, iridium and palladium.

It is preferred to use the same organic solvent or the same mixture ofsolvents for both steps. A particularly appropriate group of solventsfor carrying out the process of the present invention on a large scaleis the group of non inflammable halogenated hydrocarbons.

Suitable hydrocarbons are disclosed, for instance, in the patent toRoselius, No. 2,048,624, as carbon tetrachloride, acetylene dichloride(sym-dichloroethylene), chloroform, and methyl dichloride.

The process of the present invention is preferably carried out at roomtemperature and atmospheric pressure.

The industrial application of the process of the invention is preferablycarried out on cut tobacco when conveyed along by the processing chain.The operation of preparing the fiber will preferably last a short periodonly. If e.g. carbon tetrachloride is used as the permeabilityrnodifyingagent in the first step and as solvent in the impregnation mixture inthe second step, it is caused to act on the fiber for about one hour. Asolvent tobacco ratio of 1.6 by weight has been found to give bestresults.

Carbon tetrachloride is preferred as the solvent in the preparatory stepand carbon tetrachloride mixed with 0.1% of aluminum diethyl malonate ispreferred as impregnant for the impregnation step.

In the actual impregnating operation following immediately the preparingoperation, the tobacco is treated and preferably sprayed with a smallamount of the impregnation mixture. In certain cases the preparation andthe impregnation of the fiber will be carried out simultaneously byadmixing the metal containing substance to the solvent used for thepreparing operation.

The following non-limitativ-e examples illustrate how the processaccording to the invention is carried out in practice:

Example 1 parts by weight of Maryland tobacco being conveyed along theprocessing chain in the production of cigarettes, are introduced, afterbeing cut in the conventional manner, into parts by Weight of carbontetrachloride containing dissolved therein 0.1% by weight of aluminumdiethyl malonate. The cut tobacco is left for one hour in contact withthe liquid, and is then removed from excess liquid, if any is left.Residual solvent evaporates rapidly at the air. The conventionaltreatment in the processing chain then continues.

Example 2 100 parts by weight of Maryland tobacco are introduced, afterbeing cut, into 160 parts by weight of carbon tetrachloride and left forabout 1 hour in contact therewith. The cut tobacco is then removed fromexcess liquid, if any is left, and sprayed with a solution of about 0.1%of aluminum diethyl malonate in carbon tetrachloride to impregnate thecuttings. The solvent is permitted to evaporate from the impregnatedcuttings. The conventional treatment in the processing chain thencontinues,

The results obtained by the process of the present invention areillustrated on two samples of Maryland tobacco which have been treatedin accordance with this process on a semi-industrial scale and analysed.The values given in the following table were obtained by analysis of thecondensate of smoke produced from treated and untreated tobacco,respectively:

Analysis of smoke produced from acco The values in the above table aregiven in micrograms per 100 cigarettes. They clearly show the effect ofthe treatment on the composition of the cigarette smoke. The inventionprovides a process which allows in a reproduceable Way a decrease of4060% of polycyclic hydrocarbons, whereby the amount of pentacyclichydrocarbons is more reduced than the amount of triand tetracyclichydrocarbons.

We claim:

1. A method for treating tobacco for the purpose of modifying itscombustion process to thereby diminish the amount of carcinogenicsubstances formed during the combustion, comprising the step ofimpregnating tobacco at room temperature and under atmospheric pressurewith a mixture consisting essentially of an organo-metallic compoundselected from the group consisting of the alcohalates andorgano-metallic acids of aluminum, magnesium, cadimium, bismuth andiron, and volatile, liquid non-inflammable halogenated hydrocarbon inexcess of the amount of tobacco being treated, in which hydrocarbon saidorgano-metallic compound is dispersed, thereby obtaining a tobacco, thesmoke of which has a greatly reduced content of polycyclic hydrocarbons.

2. A method as described in claim 1, wherein the organo-metalliccompound is aluminum diethyl malonate.

3. A method as described in claim 1, wherein the hydrocarbon is carbontetrachloride.

4. A method as described in claim 1, wherein said mixture consistsessentially of carbon tetrachloride mixed with 0.1% of aluminum diethylmalonate.

5. A method for treating tobacco for the purpose of modifying itscombustion process to thereby diminish the amount of carcinogenicsubstances formed during the combustion, comprising:

(a) pre-treating tobacco with an excess amount of volatile, liquidnon-inflammable halogenated hydrocar- 4 bon, thereby modifying thepermeability of the vegetative cells thereof; and

(b) impregnating the pre-treated tobacco at room temperature and underatmospheric pressure with an impregnation mixture selected from thegroup consisting of (I) a mixture consisting essentially of anorgano-metallic compound and volatile, liquid non-inflammablehalogenated hydrocarbon in which said organo-metallic compound isdispersed,

(II) a suspension of a metallic substance in non-inflammable halogenatedhydrocarbon; wherein said organo-metallic compound is selected from thegroup consisting of the alcoholates and organo-metallic acids ofaluminum, magnesium, cadmium, bismuth and iron; and wherein saidmetallic substance is selected from the group consisting of elementalaluminum, magnesium, manganese, cadmium, bismuth, iron, platinum,iridium and palladium, the oxides thereof, and salts thereof which aretransformable at a temperature above 500 C. to an oxidation stage of therespective metal ranging from the elemental metal to the metal oxidestage, thereby obtaining a tobacco, the smoke of which has a greatlyreduced content of polycyclic hydrocarbons.

6. A method as described in claim 5, wherein the weight ratio of saidhydrocarbon to the tobacco pretreated therewith is about 1.6.

7. A method as described in claim 5 wherein the time of pretreatment isone hour.

8. Tobacco treated according to the process described in claim 1.

9. Tobacco treated according to the process described in claim 5.

References Cited in the file of this patent UNITED STATES PATENTS345,076 Robinson July 6, 1868 665,791 Love Aug. 14, 1900 2,859,753Hitchcock et a1. Nov. 11, 1958 2,902,998 Durandeaux Sept. 8, 1959FOREIGN PATENTS 567,098 Germany Apr. 26, 1933 670,855 Germany Jan. 26,1939 599,816 Great Britain Mar. 22, 1948 1,131,423 France Oct. 22, 195668,053 France Oct. 14, 1957 5 1,180,320 France Dec. 29, 1958

1. A METHOD FOR TREATING TOBACCO FOR THE PURPOSE OF MODIFYING ITSCOMBUSTION PROCESS TO THEREBY DIMINISH TO AMOUNT OF CARCINOGENICSUBSTANCES FORMED DURING THE COMBUSTION, COMPRISING THE STEP OFIMPREGNATING TOBACCO AT ROOM TEMPERATURE AND UNDER ATMOSPHERIC PRESSUREWITH A MIXTURE CONSISTING ESSENTIALLY OF AN ORGANO-METALLIC COMPOUNDSELECTED FROM THE GROUP CONSISTING OF THE ALCOHALATES ANDORGANO-METALLIC ACIDS OF ALUMINUM, MAGNESIUM, CADIMIUM, BISMUTH ANDIRON, AND VOLATILE, LIQUID NON-INFLAMMABLE HALOGENATED HYDROCARBON INEXCESS OF THE AMOUNT OF TOBACCO BEING TREATED, IN WHICH HYDROCARBON SAIDORGANO-METALLIC COMPOUND IS DISPERSED, THEREBY OBTAINING A TOBACCO, THESMOKE OF WHICH HAS A GREATLY REDUCED CONTENT OF POLYCYCLIC HYDROCARBONS.